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Arctic sea ice is melting at its fastest pace in
almost 40 years
The Northwest Passage was, again, free of ice this summer and the polar region could be
unfrozen in just 30 years
• Arctic may be ice-free within 30 years
• Melting Arctic ice releasing banned toxins, warn scientists
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John Vidal, environment editor
guardian.co.uk, Sunday 11 September 2011 17.20 EDT
Article history
Aerial view of the Petermann glacier, Greenland’s north-west coast – a 100 square-mile block of
ice broke off it in August last year; by July this year it had melted. Photograph: Nick
Cobbing/AFP/Getty Images
Arctic sea ice has melted to a level not recorded since satellite observations started in 1972 – and
almost certainly not experienced for at least 8,000 years, say polar scientists.
Daily satellite sea-ice maps released by Bremen university physicists show that with a week's
more melt expected this year, the floating ice in the Arctic covered an area of 4.24 million square
kilometres on 8 September. The previous one-day minimum was 4.27m sq km on 17 September
2007.
The US National Snow and Ice Data Centre (NSIDC) in Boulder, Colorado, which also tracks
the extent of sea ice, has not posted data for a week but is expected to announce similar results in
the next few days.
The German researchers said the record melt was undoubtedly because of human-induced global
warming. "The sea-ice retreat can no more be explained with the natural variability from one
year to the next, caused by weather influence," said Georg Heygster, head of the Institute of
Environmental Physics at Bremen.
"It seems to be clear that this is a further consequence of the man-made global warming with
global consequences. Climate models show that the reduction is related to the man-made global
warming, which, due to the albedo effect, is particularly pronounced in the Arctic," he said. The
albedo effect is related to a surface's reflecting power – whiter sea ice reflects more of the sun's
heat back into space than darker seawater, which absorbs the sun's heat and gets warmer.
Floating Arctic sea ice naturally melts and re-freezes annually, but the speed of change in a
generation has shocked scientists – it is now twice as great as it was in 1972, according to the
NSIDC, with a decline of about 10% per decade.
Arctic temperatures have risen more than twice as fast as the global average over the past half
century.
Separate, less reliable, research suggests that Arctic ice is in a downward spiral, declining in area
but also thinning. Using records of air, wind and sea temperature, scientists from the Polar
Science Centre of the University of Washington, Seattle, announced last week that the Arctic
sea-ice volume reached its lowest ever level in 2010 and was on course to set more records this
year.
The new data suggests that the volume of sea ice last month appeared to be about 2,135 cubic
miles – just half the average volume and 62% lower than the maximum volume of ice that
covered the Arctic in 1979. The research will be published in a forthcoming issue of the Journal
of Geophysical Research.
If current trends continue, a largely ice-free Arctic in the summer months is likely within 30
years –that is up to 40 years earlier than was anticipated in the last Intergovernmental Panel on
Climate Change (IPCC) assessment report.
The last time the Arctic was uncontestably free of summertime ice was 125,000 years ago, at the
height of the last major interglacial period, known as the Eemian.
"This stunning loss of Arctic sea ice is yet another wake-up call that climate change is here now
and is having devastating effects around the world," Shaye Wolf, climate science director at the
Centre for Biological Diversity in San Francisco told journalists.
Arctic ice plays a critical role in regulating Earth's climate by reflecting sunlight and keeping the
polar region cool. Retreating summer sea ice is widely described by scientists as both a measure
and a driver of global warming, with negative impacts on a local and planetary scale.
This year, both the North-west and North-east passages were mostly ice free, as they have been
twice since 2008.
Last month, the 74,000-tonne STI Heritage tanker passed through the North-east Passage with
the assistance of ice breakers in just eight days on its way from Houston, Texas, to Thailand.
The north-east sea route, which links the Atlantic to the Pacific, is likely to become a commercial
ship operator's favourite, saving thousands of miles and avoiding tolls on the Suez Canal tolls.
Further evidence of dramatic change in the Arctic came last week from Alan Hubbard, a Welsh
glaciologist at Aberystwyth University, who has been studying the Petermann glacier in northern
Greenland for several years.
The glacier, which covers about 6% of the icecap, is 186 miles (300km) long and up to 3,280ft
(1km) high. In August last year, a 100 square-mile (260 sq km) block of ice calved from the
glacier. Photographs show that by July this year it had melted and disappeared.
"I was gobsmacked. It [was] like looking into the Grand Canyon full of ice and coming back two
years later to find it full of water," said Hubbard.
Last year (2010) tied with 2005 as the warmest year on record.
• This article was amended on 16 September 2011 to remove an inaccurate quote.
1.) How long has the Arctic Ocean been impossible to sail through?
2.) What affect have CO2 emissions had on the arctic?
3.) Explain “the Albedo Effect”.